Reduced test cases

Introduction

We use the WebKit project documentation as a reference guide for writing a reduced test case (http://webkit.org/quality/reduction.html). After reading the documentation on the WebKit site, refer to the tips and examples below for further help creating reduced test cases for Chromium.

Helpful tips

Using Chromium's Web inspector to understand the problem makes it easy to create a reduction.

Get rid of unnecessary <div> and <a> tags.

Replace <table> tags with <div> tags.

If an issue has to do with overlaps or misalignment, add a border to the elements to see how they're being rendered.

Remove images. If an issue doesn't relate to an image itself, remove the src value in the <image> tag, set height and width, and specify a border:

<img src="" width="70" height="70" style="border:1px solid red">

With scripting issues, once the responsible scripts have been identified, check the path followed by different browsers and remove unnecessary functions and lines of code.

Examples

We've created a couple of examples that walk through the process of reducing a website bug into a reduced testcase.

The edit-simplify method example takes an Orkut bug that we encountered in the past, and goes through a step-by-step process of reducing 500 lines of HTML code into 35 lines.

Also useful is an example using Chromium's element inspector. Beginning with the same bug as the edit-simplify method, this example shows how to isolate the page element causing the issue.